<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>bootstrap</title>
    <link rel="stylesheet" href="../bootstrap-4.3.1-dist/css/bootstrap.css">
    <script src="../jQuery/jquery-1.12.4.js"></script>
    <!--引入bootstrop.js之前引入js-->
    <script src="../bootstrap-4.3.1-dist/js/bootstrap.js"></script>
</head>
<body>
<button class="btn btn-block">bootstrap样式</button>
<button class="btn btn-danger">bootstrap样式</button>
<button class="btn btn-dark">bootstrap样式</button>
<button class="btn btn-group">bootstrap样式</button>
<button class="btn btn-group-lg">bootstrap样式</button>
<button class="btn btn-group-sm">bootstrap样式</button>
<button class="btn btn-info"></button>
<button class="btn btn-lg"></button>
<button class="btn btn-light"></button>
<button class="btn btn-link"></button>
<button class="btn btn-outline-danger"></button>
<button class="btn btn-primary"></button>
<div class="contain">
    <div class="row">
        <div class="col">1</div>
        <div class="col">2</div>
        <div class="col">3</div>
        <div class="col">4</div>
        <div class="col">5</div>
        <div class="col">6</div>
        <div class="col">7</div>
        <div class="col">8</div>
        <div class="col">9</div>
        <div class="col">10</div>
        <div class="col">11</div>
        <div class="col">12</div>
    </div>
</div>
<div class="contain">
    <div class="row">
        <div class="col-3">1</div>
        <div class="col-3">2</div>
        <div class="col-3">3</div>
        <div class="col-3">4</div>
        <div class="col-3">5</div>
        <div class="col-3">6</div>
        <div class="col-3">7</div>
        <div class="col-3">8</div>
        <div class="col-3">9</div>
        <div class="col-3">10</div>
        <div class="col-3">11</div>
        <div class="col-3">12</div>
    </div>
</div>
</body>
</html>